A dinuclear peroxotungstate, K2[{W(=O)(O2)2(H2O)}2(ホシ-O)] ツキ 2 H2O, exhibits high catalytic performance for the epoxidn. of various allylic alcs. with only one equiv. of hydrogen peroxide at 305 K in water solvent. The effectiveness of this system is evidenced by high chemo-, regio-, and diastereoselectivity, and stereospecificity for the epoxidn. of allylic alcs. Furthermore, products/catalyst sepn. can be easily carried out by simple extn. and the catalyst recovered can be reused with the maintenance of the catalytic performance. [on SciFinder(R)]